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InterSub

InterSub offers AI-powered dual subtitles and instant word translations for language learning.

Checked 5 Oct 2026 Reviewed by Alex Listed since October 2024

Screenshot of InterSub

At a glance

Starts at $6 per month Includes unlimited word lookups, dual subtitles with AI translation, and frequent words reminders. Excludes access to mobile app integrations for free plan users.
Free tier Yes, limited
Platforms Web, Chrome, Telegram
Best for Language learners, content viewers
Not for Advanced grammar students

4.0 out of 5

Scored by Alex after real use

Our verdict

Works on multiple platforms; supports over 30 languages. Not ideal if you need extensive phonetic support or want more advanced grammar tutoring.

✓What it does well

Multi-Platform SupportWorks across YouTube, Netflix, Coursera, LinkedIn Learning, and others.
Instant TranslationsHover over words for AI-generated definitions in context.
Personal Vocabulary TrackingWords are automatically saved to your personal vocabulary list.

✕Where it falls short

Limited Phonetic SupportDoesn't provide detailed phonetic pronunciation guides.
No Advanced Grammar TutoringPrimarily focused on word translations rather than full grammar lessons.
Mobile Apps Not Included in Free PlanFree plan users don't get access to mobile app integrations like Anki.

Key features

AI-Assisted Dual SubtitlesWatch videos with subtitles in target and native languages side-by-side.
Collocation DetectionRecognizes idioms, phrasal verbs, and compound nouns for better understanding.
Remote Control Word LookupUse your phone to look up words while watching on a big screen.
Phonetic GuidesProvides detailed phonetic pronunciation guides.

Questions about InterSub

What is InterSub?

InterSub is a language learning tool that adds AI-powered dual subtitles and instant word translations to videos. It shows subtitles in the target and native languages side by side, gives in-context definitions when hovering over words, and saves looked-up words to a personal vocabulary list.

Is InterSub free?

InterSub has a free plan at $0 per month that includes a 14 day trial, with premium features on a pay-as-you-go basis. Paid access is listed at $1.56 per lookup or $6 per month, and the $6 option includes unlimited word lookups, dual subtitles with AI translation and frequent words reminders.

Which sites does InterSub work with?

InterSub works across YouTube, Netflix, Coursera, LinkedIn Learning and other sites, and it runs on the web, in Chrome and on Telegram. The reviewer notes it supports over 30 languages, and a remote control feature lets users look up words on a phone while watching on a big screen.

Does InterSub teach grammar?

Not in depth. InterSub focuses on word translations rather than full grammar lessons, so the reviewer says it is not ideal for advanced grammar students. It does recognize idioms, phrasal verbs and compound nouns, which helps learners understand expressions beyond single words.

What are the downsides of InterSub?

The reviewer lists limited phonetic support, with no detailed pronunciation guides, and no advanced grammar tutoring. Free plan users also miss out on mobile app integrations such as Anki. Toolio still scores InterSub 4.0 out of 5 after real use.

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